1. Education

Coelacanths

The best fish story of all

By

coelacanth model

Coelacanth model at the American Museum of Natural History, New York

Photo (c) Andrew Alden, licensed to About.com (fair use policy)

The world was enchanted in 1938 when an ancient type of fish, the coelacanth (SEE-la-canth), known only from fossils, was found alive, swimming in the waters off the Comoro Islands near South Africa. Coelacanth at the time was an obscure piece of scientific Latin used by fossil fish specialists, but today it's a fish with a face. For all I know, there's a coelacanth Beanie Baby (at least, there should be). And while the fish is rare in the ocean, it has a distinct presence on the Web.

Strange Among Strange

Coelacanths are a strange group (the family Actinistia) within a strange class of species, the lobe-finned fishes, which arose early in the Devonian Period some 400 million years ago. Current thinking is that they're closely related to the earliest tetrapods, the class of four-limbed creatures that gave rise to all the higher vertebrates from salamanders to human beings.

They have long, meaty fins built like stubby legs, and the living coelacanth moves them like legs as it swims. They have hinges in their skulls that allow them to bite using both upper and lower jaws. And they have an extra fin sticking out behind like a stunted fringed tail. (Here's an longer discussion of their anatomy.) But the coelacanth's name means "hollow-spine," referring to the spines in their top fin—why, fossil specialists seem rather strange too sometimes.

The lobe-finned fishes did all right for more than 100 million years, but the more familiar ray-finned fishes we all know and love (and eat) were the evolutionary winners. The last lobe-fin in the fossil record is from the Cretaceous Period, more than 65 million years ago. Apparently the survivors were species that lived in fairly deep waters, which is where today's coelacanth lives. Thus they didn't leave any fossils.

Coelacanths Today

Today there aren't many coelacanths at all. Fishing boats near the Comoros catch them by accident in their deep nets. Being inedible, they get thrown back, but they die anyway at sea-surface conditions. When a dozen coelacanths a year are killed this way, nobody knows how long the population, which may be as small as 1,000, can withstand it. And if a market for specimens were to arise—in this respect museums can be as bad as any other trophy hunter—the species might be hunted to extinction.

In previous centuries, no one would have cared much. The coelacanth would have been treated like the dodo or the passenger pigeon (which were both good eating), or the great auk (which had big eggs), or the tiger (which has a pretty hide), or the buffalo (which was just in the way).

But the 20th century marked a deep-seated change in public attitudes, and this odd, gentle fish was seen as a precious survivor from the unimaginably distant past.

When news of the coelacanth spread around the world, the authorities moved quickly to preserve this "living fossil." Many nations have put the fish on postage stamps. And when a second species of coelacanth was discovered in 1997 in Indonesia, the response was swift, including a public education campaign, scientific conferences, and events like a poster contest with support from other countries.

The world cares about these things now.

PS: Coelacanths belong to the genus Latimeria, named to honor the woman who first brought the fish to the attention of science. Marjorie Courtenay-Latimer lived to the age of 97, honored by her town and country.

  1. About.com
  2. Education
  3. Geology
  4. Fossils, Time & Evolution
  5. Fossil Creatures
  6. The Century in Review: Coelacanths

©2014 About.com. All rights reserved.